Comparison of atmospheric corrosion behavior of Al‐Mn and Al‐Zn‐Mg‐Cu alloys in a tropical coastal environment
Comparison of atmospheric corrosion behavior of Al‐Mn and Al‐Zn‐Mg‐Cu alloys in a tropical coastal environment
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DOI：
10.1002/maco.201709920
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发表时间：
2018-07
期刊：
影响因子：
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通讯作者：
Bin Wang;Xiang-bo Li;Jie Liu;Hua Jiang
中科院分区：
文献类型：
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作者：
Bin Wang;Xiang-bo Li;Jie Liu;Hua Jiang
对3A 21铝锰合金和7A 09铝锌镁铜合金的大气腐蚀行为进行了研究和比较。电化学测试结果和腐蚀形貌分析表明，在热带沿海大气环境中，3A 21和7A 09合金分别发生点蚀和晶间腐蚀（IGC），且3A 21合金的耐蚀性和再钝化能力优于7A 09合金。孔蚀转变电位Eptp可作为铝合金对可能形式的局部腐蚀敏感性的判据。7A 09合金的晶间腐蚀主要是由于晶界析出相Mg（ZnAlCu）2的优先溶解引起的，这导致了外场暴露样品的力学性能迅速劣化。通过SEM、EDX、FT-IR等分析手段对腐蚀产物层和自然氧化层的形貌和化学成分进行了表征，并对腐蚀机理进行了探讨。
Atmospheric corrosion behavior of 3A21 Al‐Mn alloy and 7A09 Al‐Zn‐Mg‐Cu alloy were investigated and compared. Electrochemical results, together with corrosion morphology characterization, suggest that in tropical coastal atmosphere, 3A21 and 7A09 alloys suffer pitting corrosion and intergranular corrosion (IGC), respectively, and 3A21 alloy shows better corrosion resistance and stronger repassivating capability than 7A09 alloy. The pit transition potential Eptp can be treated as criteria for susceptibility to possible forms of constricted localized corrosion for aluminum alloys. The IGC of 7A09 alloy is mainly caused by the preferential dissolution of the grain boundary precipitates Mg(ZnAlCu)2, and which results in fast deterioration in the mechanical properties of the field‐exposed samples. Besides, morphology and chemical compositions of native oxide layer and corrosion produces layer were characterized by SEM, EDX, and FT‐IR analysis, and the corrosion mechanism was also discussed.